Parents cautioned to ‘fight the bite' after LaCrosse cases

Published: Tuesday, September 10, 2013 at 4:30 a.m.

Last Modified: Monday, September 9, 2013 at 6:47 p.m.

A child stricken with LaCrosse encephalitis in Transylvania County and another confirmed victim in Polk County have public health officials warning parents not to let down their guard when it comes to mosquito bite prevention.

Health officials report that a child contracted LaCrosse encephalitis in July in Transylvania County, which typically averages three to four cases of the mosquito-born "arbovirus" each year.

The Polk County Health Department had one LaCrosse case confirmed in August, one of five known statewide. Nursing Supervisor Helen White wouldn't disclose the victim's age, but said the case "was acquired out of state and the patient has fully recovered."

There haven't been any reported cases so far in Henderson County, said Communicable Disease Nurse Audrey Saltz of the Health Department.

September is considered a prime month for LaCrosse infections, according to State Epidemiologist Dr. Megan Davies, with the majority of North Carolina's cases falling between late summer and early fall.

"I think it's related to the ecology of the mosquitoes and the virus," Davies said. "I think they are heavier toward the end of the summer, so I think it's an ecological phenomenon."

This year's record rainfall has created a hotbed for mosquito breeding, health officials said, including two species known to transmit the LaCrosse virus: the tree hole mosquito and the Asian tiger mosquito.

"We have evidence that there are more than usual, based on the number of mosquito complaints and concerns we've received," said Director Steve Smith of the Transylvania County Health Department. "A lot of those are nuisance complaints, but this is also a time of year (when) we get more concerned about LaCrosse."

Smith said part of the reason September traditionally sees a spike in reported LaCrosse cases could be "people kind of drop their defenses about mosquitoes" as summer segues into fall. That's a mistake, he said, since mosquitoes bearing the virus can be active until the first hard freeze.

Because children younger than 16 are more vulnerable to the LaCrosse virus, health officials urge parents to "fight the bite" by spraying kids with repellents before outside play, clothing them in long sleeves when possible and practicing what Smith called "tip-and-toss."

"The species that transmit LaCrosse are container breeders," he said. "So they breed in gutters that have stagnant water, the trays for potted plants, the old tires and birdbaths. Those things can breed a lot of mosquitoes in a short time, so people need to be vigilant about emptying them out."

Named for the Wisconsin city where it was first identified in 1963, LaCrosse encephalitis is the most common mosquito-borne disease in WNC. Most victims are either asymptomatic or experience flu-like symptoms such as headache, fever, vomiting and fatigue, said Betsy Alexander, director of nursing at the Henderson County Health Department.

However, a small percentage of victims — mostly children and the elderly — can face more dire effects, including seizures, comas and paralysis related to brain swelling, according to the U.S. Centers for Disease Control.

Deaths from the LaCrosse virus are rare, but an 8-year-old Henderson County girl succumbed to the disease in 2011 and a Transylvania County girl died from the virus in 2001.

The county works to educate people about removing or dumping containers such as old tires, Swift said, and places larvacide briquets in areas of standing water such as stormwater retention ponds. When the weather allows, the county also sprays a pyrethrin-laced aerosol that kills flying mosquitoes.

This summer's constant rain has made spraying difficult, Swift said, but the number of complaints about mosquitoes has also dropped "because people weren't outside as much." Swift expects the calls might pick up now that things have dried out, but he said a predicted cool-down later this week could suppress the bugs.

"It's all weather dependent," he said. "September is a critical month because that's when mosquito activity tends to get really intense. No one really understands why that is. But we're still spraying, we're still treating."

Overall, LaCrosse cases are down nationally and North Carolina is no exception, according to Julie Henry, spokesperson for the N.C. Department of Health and Human Services. As of Sept. 4, only 17 cases have been reported across the country. North Carolina alone had 15 cases by this time last year.

<p>A child stricken with LaCrosse encephalitis in Transylvania County and another confirmed victim in Polk County have public health officials warning parents not to let down their guard when it comes to mosquito bite prevention.</p><p>Health officials report that a child contracted LaCrosse encephalitis in July in Transylvania County, which typically averages three to four cases of the mosquito-born "arbovirus" each year. </p><p>The Polk County Health Department had one LaCrosse case confirmed in August, one of five known statewide. Nursing Supervisor Helen White wouldn't disclose the victim's age, but said the case "was acquired out of state and the patient has fully recovered."</p><p>There haven't been any reported cases so far in Henderson County, said Communicable Disease Nurse Audrey Saltz of the Health Department.</p><p>September is considered a prime month for LaCrosse infections, according to State Epidemiologist Dr. Megan Davies, with the majority of North Carolina's cases falling between late summer and early fall.</p><p>"I think it's related to the ecology of the mosquitoes and the virus," Davies said. "I think they are heavier toward the end of the summer, so I think it's an ecological phenomenon." </p><p>This year's record rainfall has created a hotbed for mosquito breeding, health officials said, including two species known to transmit the LaCrosse virus: the tree hole mosquito and the Asian tiger mosquito.</p><p>"We have evidence that there are more than usual, based on the number of mosquito complaints and concerns we've received," said Director Steve Smith of the Transylvania County Health Department. "A lot of those are nuisance complaints, but this is also a time of year (when) we get more concerned about LaCrosse."</p><p>Smith said part of the reason September traditionally sees a spike in reported LaCrosse cases could be "people kind of drop their defenses about mosquitoes" as summer segues into fall. That's a mistake, he said, since mosquitoes bearing the virus can be active until the first hard freeze.</p><p>Because children younger than 16 are more vulnerable to the LaCrosse virus, health officials urge parents to "fight the bite" by spraying kids with repellents before outside play, clothing them in long sleeves when possible and practicing what Smith called "tip-and-toss."</p><p>"The species that transmit LaCrosse are container breeders," he said. "So they breed in gutters that have stagnant water, the trays for potted plants, the old tires and birdbaths. Those things can breed a lot of mosquitoes in a short time, so people need to be vigilant about emptying them out."</p><p>Named for the Wisconsin city where it was first identified in 1963, LaCrosse encephalitis is the most common mosquito-borne disease in WNC. Most victims are either asymptomatic or experience flu-like symptoms such as headache, fever, vomiting and fatigue, said Betsy Alexander, director of nursing at the Henderson County Health Department.</p><p>However, a small percentage of victims — mostly children and the elderly — can face more dire effects, including seizures, comas and paralysis related to brain swelling, according to the U.S. Centers for Disease Control.</p><p>Deaths from the LaCrosse virus are rare, but an 8-year-old Henderson County girl succumbed to the disease in 2011 and a Transylvania County girl died from the virus in 2001. </p><p>Transylvania and Polk counties don't have publicly-run mosquito abatement programs, but Henderson County takes a three-pronged approach to fighting the buzzing disease vectors, said Environmental Health Supervisor Seth Swift. </p><p>The county works to educate people about removing or dumping containers such as old tires, Swift said, and places larvacide briquets in areas of standing water such as stormwater retention ponds. When the weather allows, the county also sprays a pyrethrin-laced aerosol that kills flying mosquitoes.</p><p>This summer's constant rain has made spraying difficult, Swift said, but the number of complaints about mosquitoes has also dropped "because people weren't outside as much." Swift expects the calls might pick up now that things have dried out, but he said a predicted cool-down later this week could suppress the bugs.</p><p>"It's all weather dependent," he said. "September is a critical month because that's when mosquito activity tends to get really intense. No one really understands why that is. But we're still spraying, we're still treating."</p><p>Overall, LaCrosse cases are down nationally and North Carolina is no exception, according to Julie Henry, spokesperson for the N.C. Department of Health and Human Services. As of Sept. 4, only 17 cases have been reported across the country. North Carolina alone had 15 cases by this time last year. </p><p>Reach Axtell at 828-694-7860 or than.axtell@blueridgenow.com.</p>